origin-sdk

This crate handles the low-level networking, cryptography, and request/response mapping of the LSX protocol, providing an asynchronous API for connecting, authenticating, and interacting with the Origin (EA Desktop) backend.

Usage

use origin_sdk::{protocol::game::GetAllGameInfo, sdk::OriginSdk};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Connect to the Origin SDK server
    let (client, _) = OriginSdk::connect("127.0.0.1:3216").await.unwrap();

    let game_info = client.send_request(GetAllGameInfo {}).await.unwrap();

    println!("{:#?}", game_info);
    // GetAllGameInfoResponse {
    //     up_to_date: true,
    //     languages: "de_DE,en_US,es_ES,es_MX,fr_FR,it_IT,ja_JP,ko_KR,pl_PL,pt_BR,ru_RU,zh_CN,zh_TW",
    //     free_trial: false,
    //     full_game_purchased: true,
    //     full_game_released: true,
    //     full_game_release_date: "0000-00-00T00:00:48",
    //     expiration: "0000-00-00T00:00:08",
    //     system_time: "2025-09-03T12:15:54",
    //     has_expiration: false,
    //     installed_version: "",
    //     installed_language: "en_US",
    //     available_version: "0.0.0.0",
    //     display_name: "Knockout City™",
    //     max_group_size: 16,
    //     entitlement_source: "EPIC",
    // }

    Ok(())
}

LSX models

All request types are defined in src/protocol and are organized by domain:

• achievements.rs
• auth.rs
• broadcast.rs
• chat.rs
• etc.

Each request implements the RequestResponse trait, which is generated by the request_response! macro. This ensures requests are automatically mapped to their corresponding ResponseBody variant:

pub enum RequestBody {
    // ...
    GetProfile(GetProfile)
    // ...
}

pub enum ResponseBody {
    // ...
    GetProfileResponse(GetProfileResponse),
    // ...
}

request_response! {
    // ...
    GetProfile => GetProfileResponse,
    // ...
}

// This call will be automatically deserialized into a `GetProfileResponse`
let profile = client.send_request(GetProfile { /* ... */ }).await?;

Cryptography

The LSX protocol uses a custom AES-128-ECB scheme with deterministic key derivation. The session key is derived through a challenge handshake with the server.

Key Notes

• AES-128-ECB + PKCS#7 padding is used for encryption and decryption
• Session keys are generated from integer seeds and are expanded into 16-byte arrays
• Pseudo-random number generator is used to produce bytes from the seed

Challenge Flow

1. The server sends a Challenge event with a random hex string key
2. The client encrypts this ASCII challenge string using AES-128-ECB with the default key
3. The encrypted data is hex-encoded into a string
4. The first two bytes of the hex string as ASCII bytes are combined into a u16 seed

   seed = (byte[0] << 8) | byte[1]
   

5. The derived seed is used to generate a new AES key and it becomes the session key for all subsequent encryption/decryption operations
6. The client sends a ChallengeResponse request back to the server, which includes:
   • The original challenge key
   • The encrypted + hex-encoded response key
   • SDK metadata (protocol version, SDK version, etc.)
7. The server sends a ChallengeAccepted response, both sides now share the same AES key

Acknowledgements

• Warranty Voider for releasing LSX-Dumper and publishing information about the protocol on various forums
• Bergmann89 for releasing xsd-parser, which helped with LSX model generation

Disclaimer

This project is a third-party reimplementation of the Origin SDK, based on reverse-engineering and observations of Origin SDK versions 9.12.1.7 and 10.6.1.8, intended for educational and research purposes only.

It is not affiliated with, endorsed by, or supported by Electronic Arts.